KYOTE Statistics and Probability 2

Question 1

A student's four test scores are 80, 85, 90, and 75. What score is needed on the fifth test to bring the average to 85?

Accepted Answer

95

Answer

A mean of 85 over 5 tests requires a total of 425; since 80+85+90+75=330, the fifth score must be 425−330=95.

Question 2

Two cards are drawn without replacement from a standard 52-card deck. What is the probability that both cards are aces?

Accepted Answer

1/221

Answer

The probability is (4/52) × (3/51) = 12/2652 = 1/221.

Question 3

In a box-and-whisker plot, which feature represents the median?

Accepted Answer

The line inside the box

Answer

The line drawn inside the box of a box-and-whisker plot always represents the median (Q2) of the data.

Question 4

A scatter plot shows a strong positive correlation between study time and test scores. What does this mean?

Accepted Answer

As study time increases, test scores also tend to increase

Answer

A positive correlation means that as one variable increases, the other tends to increase as well.

Question 5

Which measure of central tendency is most affected by extreme outlier values?

Accepted Answer

Mean

Answer

The mean uses every value in its calculation, so an extreme outlier pulls it significantly up or down.

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